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HP 4730 Cyan Print Defect

I'm working on a HP 4730MFP (a 4700 with a scanner on it). The cyan drops out on the right side (see photo). So far the cyan cartridge has been (supplies are genuine HP) and the transfer belt has also been replaced, to no avail.
What could be causing this?

This customer also gets error 49.4C.20 on the same machine. They say it occurs when they scan to email which doesn't quite fit with the description in the service manual (which describes it as a printer error). I'm leaning toward a firmware issue on this one.

Re: HP 4730 Cyan Print Defect

What do the PQ pages look like?

The 49 could be firmware related. Not sure if the 4730's are like the 4700's, in that the firmware needs to be at a certain level before being able to go right to the newest. Can't remember which level it needs to be at before loading the latest.

Re: HP 4730 Cyan Print Defect

Based on the quality pages and looking at the block diagrams in the manual I'm thinking it could be a noisy HVPS. The contacts on the cartridges and the printer have been cleaned, but that made no difference.
AC power was measured at 115V while printing so I don't think it's power related. Any thoughts?

Re: HP 4730 Cyan Print Defect

Originally Posted by Lance15

Guessing K, Y & M are okay? Only C posted.

Like 20 year tech replied, could be dirty cyan laser. Could also be a faulty toner.

All print quality pages were perfect, except for the cyan page, so only cyan was posted.
I saw this same problem a few years ago on a HP CLJ 4005 (which uses the same print engine). Only cyan was affected in that case as well. But the customer retired the printer instead of having it fixed so we never found the cause.
The genuine HP cartridge that was in use when this problem started was replaced with another genuine HP cartridge - no change in symptoms.

Re: HP 4730 Cyan Print Defect

I had many cases on image defect in these series: 4700, cp4005, and 4730. What I did is open the side of the transfer belt and fix those 2 solenoids (sticky solenoid), then do a 3 consecutive full calibration. This fixed all issues (assuming that all your cartridge are good)

Re: HP 4730 Cyan Print Defect

Originally Posted by atadikohp

I had many cases on image defect in these series: 4700, cp4005, and 4730. What I did is open the side of the transfer belt and fix those 2 solenoids (sticky solenoid), then do a 3 consecutive full calibration. This fixed all issues (assuming that all your cartridge are good)

Thanks! So, these solenoids are inside the ETB? If so, then this is not likely the cause since I installed a brand new ETB and that didn't affect the problem. So I re-installed the old ETB.
I am wondering if the shield that covers the print cartridge might not be opening fully on the left side, thereby keeping the paper from contacting the drum on that side and causing blank areas on the right side of the print.